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Cornelius J. Dennehy

Publications and source records attributed to Cornelius J. Dennehy.

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

NASA Space Observatory Precision Pointing Benchmark Problem Development

An interagency workshop in May 2021 on guidance, navigation, and control (GNC) verification and validation (V&V) methods and techniques identified needs for the formulation and public release of relevant V&V benchmark problems as a practical way forward for the discipline. A decision was made by the NASA Technical Fellow for GNC and the NASA Engineering and Safety Center (NESC) GNC Technical Discipline Team (TDT) to produce a benchmark problem focusing on the problem of space observatory precision pointing. This report contains the results of the NESC assessment.

NASA Engineering and Safety Center↗
NASA NTRS2022

NASA Engineering and Safety Center Technical Bulletin No. 22-06: Treatment of Slosh Stability Margin Reductions for Human-Rated Launch Vehicles

Slosh dynamics pose a stability concern for human-rated launch vehicles during ascent. Historical perspectives on the treatment of slosh dynamics, newly developed rules of thumb, the utility of flight data, and methods for analyzing and dispositioning slosh instability risks should be considered when linear stability margins are lower than typically accepted for human-rated systems.

Fuel Slosh↗
NASA NTRS2022

NASA Engineering and Safety Center Technical Bulletin No. 22-05: Launch Vehicle Flight Control Stability Margin Reduction Considerations

Launch vehicle ascent stability analyses typically rely on a combination of frequency and time domain analyses. Frequency domain analysis uses a sequence of high-fidelity linear models with constant parameters spanning the ascent trajectory. Complementary time domain analysis is performed using high-fidelity, nonlinear 6-DOF simulations. Analyses are typically dispersed to verify robustness to parameter variations by showing the vehicle meets frequency domain stability margin requirements and time domain performance metrics. This Technical Bulletin outlines standard stability margin best practices and provides recommendations for treatment of deviations from industry-standard launch vehicle stability margins due to vehicle flexibility, slosh dynamics, aerodynamics, other offending dynamics, or coupling thereof.

Launch Vehicle↗
NASA NTRS2022

NESC GN&C TDT Best Practices: Design Requirements for Satisfactory Handling Qualities of a Piloted Spacecraft

This document describes work to determine a proposed set of concise design requirements for manned spacecraft to yield satisfactory handling qualities when the pilot is performing manual control. This is done primary via the analysis of various historic spacecraft. Partial requirements verification is performed via the creation of a simulated pilot used to determine limits of satisfactory vehicle performance. Partial requirements validation is per-formed via example conceptual design of a spacecraft that is compliant with all relevant proposed requirements.

Cooper-Harper↗
NASA NTRS2020

Application of Micro-Thruster Technology for Space Observatory Pointing Stability

This assessment was requested by the NASA Engineering and Safety Center (NESC) Guidance, Navigation, and Control (GN&C) Technical Discipline Team (TDT), which identified the topic as an unrecognized critical need for the Agency’s future space science observatory-class space platforms. An initial low-fidelity feasibility study of the use of cold-gas micro-thrusters as a replacement for reaction wheels was performed in 2017 as a GN&C TDT discretionary activity. The assessment documented in this final report was initiated in 2018 as a follow-on high-fidelity study.

Guidance↗